Point P has coordinates of (4,4) and point Q has coordinates of (4,-4).
Since both points have the same x-coordinates we can subtract point Q's y-coordinate from point P's y-coordinate.
I will set the equation up and try and figure this part by yourself. I hope you learned what to do from previous questions that are very similar to this that I answered.
The question requires that the equation should be in the slope-intercept form. The and in this equation are constants. In particular:
would represent the slope of this line (also known as the gradient of this line,) whereas
would be the -intercept of this line.
The question states that the slope of this line is . Therefore, . Thus, the equation for this line should be in the form .
The value of constant could be found using the other piece of information: the point is in this line. In other words, the solution should satisfy the equation .
Substitute into the equation and solve for :
.
.
.
Hence, would be the slope-intercept form of the equation of this line.